In commits d0ce0e47b323 and 91a2fb956ad99, hugetlb code was changed to use page_cache_next_miss to determine if a page was present in the page cache. However, the current implementation of page_cache_next_miss will always return the passed index if max_scan is 1 as in the hugetlb code. As a result, hugetlb code will always thing a page is present in the cache, even if that is not the case. The patch which follows addresses the issue by changing the implementation of page_cache_next_miss and for consistency page_cache_prev_miss. Since such a patch also impacts the readahead code, I would suggest using the patch by Sidhartha Kumar [1] to fix the issue in 6.3 and this patch moving forward. If we would rather not modify page_cache_next/prev_miss, then a new interface as suggested by Ackerley Tng [2] could also be used. Comments on the best way to fix moving forward would be appreciated. [1] https://lore.kernel.org/linux-mm/20230505185301.534259-1-sidhartha.kumar@xxxxxxxxxx/ [2] https://lore.kernel.org/linux-mm/98624c2f481966492b4eb8272aef747790229b73.1683069252.git.ackerleytng@xxxxxxxxxx/ Mike Kravetz (1): page cache: fix page_cache_next/prev_miss off by one mm/filemap.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) -- 2.40.1
